import java.net.*;
public class BroadCast  { 
	   String s="国庆放假时间是9月30日"; 
	      int port=5858;                                    //组播的端口 
	         InetAddress group=null;                          //组播组的地址
		    MulticastSocket socket=null;                     //多点广播套接字  
		       BroadCast() { 
			             try { 
					              group=InetAddress.getByName("239.255.8.0");//设置广播组的地址为239.255.8.0
						               socket=new MulticastSocket(port);         //多点广播套接字将在port端口广播
							                socket.setTimeToLive(1); //多点广播套接字发送数据报范围为本地网络
									         socket.joinGroup(group); //加入group后,socket发送的数据报被group中的成员接收到
										       }                                 
				           catch(Exception e) {
						            System.out.println("Error: "+ e);          
							          }
					      }
		          public void play() {
				        while(true) {
						        try{   DatagramPacket packet=null;        //待广播的数据包
								               byte data[]=s.getBytes(); 
									                      packet=new DatagramPacket(data,data.length,group,port); 
											                     System.out.println(new String(data)); 
													                    socket.send(packet);             //广播数据包
															                   Thread.sleep(2000);
																	           }
							        catch(Exception e) {
									               System.out.println("Error: "+ e);          
										               }
								      }
					   }
			     public static void main(String args[]) {
				           new BroadCast().play();
					      }
}
